The Mesoamericans were robust users of rubber, according to historical and archaeological records. With it they made sandals, rubber bands and also balls, which they used to play a ceremonial game in stone-walled courts.
Each of these items need different qualities in the rubber of which they are made. A ball requires elasticity for bounciness, a rubber band requires strength, and a sandal requires wear and resistance.
A new study reports that the Mesoamericans, which include the Aztec and the Maya, knew how to make different kinds of rubber, mixing latex from rubber trees with juice squeezed from morning glory vines in different proportions.
“It’s a pretty safe bet that they were engineering materials to suit their needs,” said Michael Tarkanian, the study’s lead researcher and a materials scientist at M.I.T. “It wasn’t just a haphazard concoction.”
Mr. Tarkanian and his co-author, Dorothy Hosler, also an M.I.T. researcher, experimented with samples of latex and morning glory vine juice from Mexico and achieved three kinds of rubber with different mixtures.
Bounciness is maximized when 50 percent of the mixture is juice, while longevity and wear are maximized when 25 percent of the mixture is juice. And strength, required for a rubber band, is maximized when no juice is added.
The earliest records indicate that Mesoamericans were using rubber by 1600 B.C. Thousands of years later, in 1839, Charles Goodyear discovered vulcanization, the chemical process used to produce rubber today.
The research will be published in an upcoming issue of Latin American Antiquity.
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References:
Bhanoo, Sindya N. 2010. "Ancient Mesoamerica’s Rubber Industry". New York Times. Posted: June 21, 2010. Available online: http://www.nytimes.com/2010/06/22/science/22obrubber.html
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